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One hot topic facing the maritime industry at the moment is the question of alternative fuels. The word ‘alternative’ here being used to describe fuels such as LNG and CNG. The relevance of this subject can be seen in how close it lies to the issues of emissions regulations, fuel costs and sustainability.


Why is C-Job in a position to discuss such matters? As an independent Ship Design and Engineering company, it is C-Job’s role to have its finger on the pulse of industry developments. For example, C-Job’s Design Director and Head of Engineering (Basjan Faber and Tim Vlaar) recently shared their experiences of designing alternative-fuelled vessels during a presentation at the Maritime Technology department of the Royal Dutch Organisation of Engineers (KIVI). To illustrate their findings, they used the two recently completed vessels as examples: the hybrid CNG-Electric ferry Texelstroom owned by TESO and DEME’s LNG-powered trailing suction hopper dredger Bonny River.



Photo: Texelstroom


Need to know

The knowledge that C-Job has built up with these two vessels can help ship owners discuss the most pertinent points in the switch to an alternative fuel. There are quite a few issues to consider:

  • Diesel costs vs. natural gas costs
  • Costs of newbuilding or conversion to natural gas
  • Costs of diesel systems with after-treatment systems (scrubbers)
  • Availability of natural gas and distribution costs
  • Costs of crew training
  • On board safety
  • Environmental impact

In addition to the economic issues to take into account, ship owners also need to be aware of the rules and regulations. In Emission Control Areas (ECAs), sulphur and/or nitrogen oxide emissions are limited. The owner of a vessel sailing in an ECA has to choose between using an exhaust gas cleaning system or switching to low sulphur fuel. In contrast, in selecting the natural gas alternative, a vessel’s emissions are automatically within ECA limits.


Sharing the knowledge

In discussing the pros and cons of LNG and CNG, it must be said that LNG is more established in the maritime sector. And although bunkering logistics remain a sticking point, there are other facts to bear in mind when considering it as a fuel. First and foremost, it is a cryogenic material that needs to be stored below -160C°. For crews used to dealing with diesel (a relatively non-hazardous material compared to LNG), there are a lot of safety considerations. This is just a small part of the experience that C-Job has built up with the ship design of several LNG and CNG projects regarding Dredging, Heavy Lift, Ferries, Tugs and other projects.


CNG, on the other hand, is quite different. Although it is used quite a lot in the automotive industry, it is still in the early stages when it comes to shipping. This means that, as yet, there are no regulations available for bunkering CNG in the maritime industry. For example, regulations for handling on board gases are only available up to pressures of 10 bars. Because CNG is often stored at 250 bars, a situation is reached when an engineering company has to create guidelines in cooperation with a classification society. This is precisely what C-Job achieved with the Texelstroom: while looking at existing solutions from the automotive industry, the Class-approval process was actually started from scratch together with Lloyd's Register.


Switching to LNG or CNG

The Texelstroom is a perfect case for CNG because it has a relatively short range and its tanks can be filled at night. Therefore, this operational profile would also suit vessels operating in harbours; port authorities, port operations and police boats, for instance. Conversely, LNG is more suitable for ships with a larger, more international range.


"Looking further ahead, C-Job sees the use of fuels like LNG and CNG as a transition towards even more advanced types of alternative fuels."


In terms of more environmentally friendly shipping, both LNG and CNG have advantages. Both are cleaner fuels in terms of nitrogen and sulphur emissions (NOx and SOx) as well as particulate matter, but both are still hydrocarbon-based fuels that release CO2 into the atmosphere. Looking further ahead, therefore, C-Job sees the use of fuels like LNG and CNG as a transition towards even more advanced types of alternative fuels such as hydrogen and ammonia. There are interesting times ahead – and C-Job will keep up to date and keep you informed.

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